Answer:
penicillin could protect mice against infection from deadly Streptococci.
Explanation:
Answer:
In 1940, Florey carried out vital experiments, showing that penicillin could protect mice against infection from deadly Streptococci.
Scientists use carbon dating to determine the age of fossils. 14C is a rare isotope of carbon that has a half life of 5730 years and decays into 14N. By measuring the amount of 14C remaining in a fossil, scientists can estimate when the organism died out to about 60,000 years. The atomic number of C is 6, and of N is 7. 14C and 14N have the same: Group of answer choices
Answer:
The correct answer is - mass number.
Explanation:
The atomic number the number of electrons or protons present in a neutral atom.
Atomic number = Number of electrons = Number of protons
Whereas, the mass number the sum of the number of protons and the number of neutrons present in an atom.
Mass number = Number of protons + Number of neutrons
For C-14 and N-14:
C-14 isotope:
Atomic number = number of proton = number of electron = 6.
Mass number = 14
Number of neutrons = 14 - 6 = 8
In N-14 isotope:
Atomic number = number of proton = number of electron = 7
Mass number = 14
Number of neutrons = 14 - 7 = 7
Thus, these two isobars have same mass number.
Which of the following answer describes 1-pentyne?
O structure should have 5 carbon with double bond beginning on the 1st carbon atom
O structure should have 6 carbon with triple bond beginning on the 1st carbon atom
O structure should have 6 carbon with double bond beginning on the 1st carbon atom
O structure should have 5 carbon with triple bond beginning on the 1st carbon atom
Answer:
The answer is that the structure should have 5 carbon with triple bond beginning on the 1st carbon atom.
Explanation:
The structure will have 5 carbons since the -pent prefix means 5 carbons.
The structure has a triple bond because the -yne suffix means that the structure is an alkyne. An alkyne is a hydrocarbon with triple covalent bonds.
Also, the position of the triple bond is known because the nomenclature of the alkyne states that the triple bond is on the 1st carbon.
What is the percent yield of a reaction that has a theoretical yield of 50.0 grams of product but after an experiment you only collect 40 grams of product?
May solution ba o wala tanong kolang
The percent yield of a reaction is 80%
The theoretical yield of the product is 50.0 g
The actual yield of the product is 40 g
We need to calculate the percent yield of the reaction.
What is the percent yield?
The percent yield describes the ratio of the actual yield and the theoretical yield expressed as a percentage value.
The formula of percent yield is shown as
[tex]Percent\ yield =\ \frac{actual\ yield} {theoretical\ yield} \times 100[/tex]
Now, putting the given values as
[tex]Percent\ yield =\ \frac{40} {50} \times 100[/tex]
Percent yield = 80 %
Therefore, the percent yield of a reaction is 80%
To learn more about percent yield, click here:
https://brainly.com/question/2506978
Which rock among the given rocks is most likely to erode away the fastest?
Please give 1 answer.
A.
Marble
B.
Granite
c
.
Sandstone
D.
Basalt
Answer:
The answer is B............
Answer:
b. Granite
Explanation:
Soft rock like chalk will erode more quickly than hard rocks like granite. Vegetation can slow the impact of erosion. Plant roots adhere to soil and rock particles, preventing their transport during rainfall or wind events.
Mark as Branliest
increases/decreases from left to right across a period.WHY do we observe this periodic trend?
Answer:
don't no answer
Explanation:
d don't no answer
If 0.500 moles of silver nitrate were consumed, how many moles of calcium nitrate would be produced?(make sure to balance the chemical equation first)
AgNO3 + CaCl2 → Ca(NO3)2 + AgCl
Answer:
Explanation:
AgNO3 + CaCl2 ⇒ Ca(NO3)2 +AgCl
2AgNO3 + CaCl2 ⇒ Ca(NO3)2 + 2AgCl
what is the volume of 72g of copper has a density of 9/cm 3
Answer:
8cm³
Explanation:
density = mass/volume
or volume = mass/density
= 72/9
= 8 cm³
A baseball player hits a ball. Which is the best description of the energy of the ball as it flies over the pitcher's head?
O chemical
O kinetic
O nuclear
O thermal
The simple activities like walking, jumping, throwing and falling usually involves kinetic energy. Here the energy of ball when a baseball player hits a ball is kinetic energy. The correct option is B.
What is kinetic energy?The kinetic energy of an object is defined as the measure of the work that an object does by virtue of its motion. When work is done on an object, energy is transferred and the object moves with a constant speed. This energy transferred is kinetic energy.
It is possible to transfer kinetic energy between objects and can be transformed into other form of energy. The SI unit of kinetic energy is Joule and it is proportional to the square of velocity and mass of the object.
Here the moving ball has kinetic energy due to its stae of motion.
Thus the correct option is B.
To know more about kinetic energy, visit;
https://brainly.com/question/22174271
#SPJ7
explain observation made when anhydrous calcium chloride and anhydrous copper (ii) sulphate are separately exposed to the atmosphere for about two days
Answer:
Anhydrous calcium chloride dissolves and becomes liquid
Anhydrous copper (ii) sulphate will produce crystal particles
Explanation:
Anhydrous calcium chloride is deliquescent and hence when it is exposed to air, it absorbs water from air. After absorbing water, it dissolves and after some time a pool of clear liquid appears.
Anhydrous copper (ii) sulphate will form crystal structures and the following reaction will takes place
CuSO4 + 5 H20 --> CuSO4.5H2O
Unit Test Review
Active
1
2
3
According to the kinetic-molecular theory, what happens to a liquid when it is transferred from one container to
another?
O The volume and the shape stay the same.
O The volume increases to fill the new container, but the shape stays the same.
O The volume stays the same, but the shape changes to fit the new container
O The volume and the shape change to fill the new container
Answer:
the volume stays the same, but the shape changes to fit the new container
Explanation:
because the same amount/volume of liquid is being placed in a new container, the new container has a different shape to the old, thus changing the liquids shape but not volume.
Which statement about Niels Bohr’s atomic model is true?
Answer:
Each orbit has a specific energy level.
Would you mind marking it the brainliest:).
The table shows data from an experiment designed to find a solution that is both an acid and a strong electrolyte. Based on the data, which solution is the best acidic electrolyte.
Solution 1, 2, 3, or 4? Thank you!!!
Answer:
Solution 4 is the best acidic electrolyte
Explanation:
An acidic medium such as a solution has a pH that is less than 7. The acidity of the medium increases with decrease in the pH value. Acidic solutions turn blue litmus solution red. They produce hydrogen ions as positive ions solution as well as a negatively-charged ion.
An electrolyte is a solution which allows electric current to pass through it and in the process is decomposed by the electric current. Electrolytes are able to allow current flow through them because they are composed of negatively and positively-charged molecules known as ions which are responsible for carrying electrical charges. A good electrolyte will be a solution which conducts electricity freely.
Based on the data in the table, the solution that is both acidic and has high electrical conductivity is solution 4. Solution 4 turns blue litmus solution red indicating that it is acidic. Also, it has a low pH of 2.0 indicating that it is very strongly acidic.
Therefore, solution 4 is the correct option.
A female rabbit had 4 babies. For phenotypes: two of the babies were black and two of the babies were white. In rabbits, the allele for black fur (B) is dominant to the allele for white fur (b). Identify the genotypes of the mom and dad rabbit and complete the Punnett square to show how the 4 babies got their fur color.
Answer:put the rabbits mixed
Explanation:
explain what you understand by valency, give examples
Answer:
Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element.
Example:
One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.
Phosphorous is prepared according to the following equation: Ca3(PO4)2 + 3SiO2 + 5C = 3CaSiO3 +5CO + 2P
What mass of phosphate rock (Ca3(PO4)2) is necessary to produce 9700. kg of phosphorous?
Answer:
48546.7kg or 48546745g
Explanation:
so from this u can work out the amount of moles in phosphorous by doing mass / mr you have to convert the mass in kg to g so you times it by 1000. then divide it by 31 which is the mr of phosphorous. then u can use the molar ratio which is 2:1 . Then use the equation mass= moles*mr
so 97000*1000/31=312903moles
2:1
so 312903/2=156451 moles of ca3(PO4)2
so mass= moles*mr
156451*310.3=48494g
hope this helps u to understand(*°▽°*)
Adam is doing a science project. He wants to find out how the height of the Sun affects the length of shadows. He will measure the shadow of his house at different times. He will see when the shadow is the longest.
Which is a scientific prediction Adam could make about his project?
A.
The Sun is highest at noon.
B.
The shadow will be longest in the morning.
C.
My shadow is shorter than the shadow of my house.
D.
I found out that the shadow is shortest at noon.
Answer:
d I think there's two answer
Explanation:
or c
Match each element or compound with the appropriate symbol or molecular formula. Carbon dioxide CO2 carbon o oxygen Н H water с hydrogen H2O
Answer:
Carbon dioxide ---> CO₂
Water ----> H₂O
Carbon ---> C
Oxygen ----> O₂
Hydrogen ----> H₂
Explanation:
The molecular formula of an element or compound is a formula which represents the composition of a molecule of that element or compound. It consists of the formula representing the atoms present as well as the number of atoms of each element innthe compound written as subscript innthe formula of the element or compound.
The molecular formula of the given elements and compounds are given below:
Carbon dioxide ---> CO₂
Water ----> H₂O
Carbon ---> C
Oxygen ----> O₂
Hydrogen ----> H₂
The molecular formula of carbon dioxide shows that in a molecule of carbon dioxide, there are two atoms of oxygen and one atom of carbon present in a molecule of carbon dioxide.
The molecular formula of water shows that are two atoms of hydrogen and one atom of oxygen present in a molecule of water.
The molecular formula of carbon shows that there are one carbon atoms in a molecule of carbon.
The molecular formula of oxygen shows that there are two oxygen atoms in a molecule of oxygen gas.
The molecular formula of hydrogen shows that there are two molecules of hydrogen in a molecule of hydrogen gas.
ASAP PLS
Identify the correct formula for each of the following compounds.
Carbon tetrabromide
4CBr
CBr4
C4Br
Chlorine monofluoride
ClF
FCl
Cl1F1
Answer:
1.CBr4
2.CIF
Explanation:
Covalent compound are formed by sharing of electron and ionic compound formed by complete transfer of electron. The chemical formula for Carbon tetrabromide is CBr₄ and for Chlorine monofluoride is ClF.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
Ionic compounds are more stronger than covalent compound. Ionic compounds have higher melting and boiling point than covalent compounds.
The chemical formula for Carbon tetrabromide is CBr₄, tetra means four. The chemical formula for Chlorine monofluoride is ClF, mono means one.
Therefore, the chemical formula for Carbon tetrabromide is CBr₄ and for Chlorine monofluoride is ClF.
To learn more about chemical compound, here:
https://brainly.com/question/26487468
#SPJ2
Which of the following correctly describes the role of the mouth in the digestive system?
The mouth acts like a muscular bag by churning the food and producing enzymes that aid in chemical digestion.
The mouth produces all of the enzymes needed for digestion and these enzymes are swallowed, which moves them through the digestive tract.
The mouth begins the process of digestion by mechanically breaking food into smaller pieces.
The mouth performs the peristalsis that pushes food through the rest of the digestive system.
Answer:
The mouth begins the process of digestion by mechanically breaking food into smaller pieces.
Explanation:
Digestion is a crucial process that involves the break down of complex food molecules into simpler ones that are assimilable by the body. The process of digestion in humans, for example, is said to begin in the MOUTH where the food enters through.
The mouth via the use of teeth helps the initially break down the food particles using mechanical/physical method. This further helps the break down of the food into tiny particles before they are acted on enzymatically.
(b) When water reacts with potassium metal the hydrogen produced ignites explosively
on the surface of water.
(ii) Write an equation to show how this ignition occurs.
2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
A student creates a model of a closed ecosystem by filling a glass tank half
full with water, then adding 10 snails and two small aquatic plants. The next
day, all the snails are dead. What is the most likely cause of their death?
A. The rates of cellular respiration and photosynthesis in the tank
were both too high.
B. The rates of cellular respiration and photosynthesis in the tank
were both too low.
O C. The rate of cellular respiration in the tank was much higher than
the rate of photosynthesis.
D. The rate of photosynthesis in the tank was much higher than the
rate of cellular respiration.
SUBMIT
e
PREVIOUS
Answer:
C. The rate of cellular respiration in the tank was much higher than
the rate of photosynthesis
Explanation:
In nature, cellular respiration and photosynthesis are opposite metabolic reactions. Cellular respiration, which is the process of releasing energy, requires oxygen while photosynthesis, which is the process of manufacturing foods by green plants, releases oxygen into the atmosphere. The two equations are as follows:
Photosynthesis:
6CO2 + 6H2O → C6H1206 + 6O2 (oxygen released)
Respiration:
C6H1206 + 6O2 (oxygen used) → 6CO2 + 6H2O
According to this question, 10 snails and two small aquatic plants were added to a closed glass tank half full with water. It was observed that all the snails died. This is most likely due to the fact that the rate of cellular respiration in the tank was much higher than the rate of photosynthesis.
In other words, the usage of oxygen via cellular respiration was much higher than the release of oxygen via photosynthesis.
Answer:
1. Snails carry out respiration only
2. Aquatic plants carry out both respiration and photosynthesis Although the aquatic plants can absorb carbon dioxide and release oxygen through photosynthesis, the amount of snail is much more than that of the aquatic plants.
During night time,the absence of light prevent the plants from carrying out photosynthesis. No oxygen is released at this time. There is a net release of carbon dioxide in the closed system and hence the snail died of suffocation.
A gas initially has a volume of 300. mL at a pressure of 1.0 atm, what will the
new volume be if the pressure is doubled? (assume constant temperature)
If 11 kJ of heat is transferred to 2300 g of soil at 21°C, what would the new temperature of the soil be?
Answer:
26.98°C
Explanation:
Applying,
Q = cm(t₂-t₁)................ Equation 1
Where Q = Heat transferred to the soil, c = specific heat capacity of dry soil, m = mass of the soil, t₂ = final temperature, t₁ = initial temperature.
From the question,
Given: Q = 11 kJ = 11000 J, m = 2300 g = 2.3 kg, t₁ = 21°C
Constant: c = 800 J/kg.°C
Substitute these values into equation 1
11000 = 800×2.3(t₂-21)
Solving for t₂
t₂-21 = 11000/(800×2.3)
t₂-21 = 11000/1840
t₂-21 = 5.98
t₂ = 5.98+21
t₂ = 26.98°C
If 81g of water is measured out, how many moles are in the sample? *
A. 4
B. 5
C. 2.5
D. 4.5
Answer:
D
Explanation:
because moles = mass /mr
so 81/18(mr of H2O=2+16)
moles =4.5
hope this helps:)
how are molarity and volume related
these are the options
A They are directly related.
B They are inversely related.
C They are different units of dilution.
D They are different units of concentration.
Answer:
Molarity can be used to calculate the volume of solvent or the amount of solute. The relationship between two solutions with the same amount of moles of solute can be represented by the formula c1V1 = c2V2, where c is concentration and V is volume.
The relationship between Molarity and volume of a solution is : ( B ) They are inversely related
What is molarity ?Molarity is the number of moles of solute in unit of volume of the solution ( usually per liter ). Molarity is calculated by dividing the number of moles of a solute ( n ) by the volume of the solution.
Molarity = n / v .
Therefore we can conclude that the relationship between Molarity and volume is that they are inversely related.
Learn more about Molarity : https://brainly.com/question/17138838
Which represents a balanced nuclear equation?
WHY DOES TEMPERATURE REMAIN CONSTANT DURING CHANGE OF STATE
QUESTION
WHY DOES TEMPERATURE REMAIN CONSTANT DURING CHANGE OF STATE
[tex]\huge\mathbb{\red A \pink{N}\purple{S} \blue{W} \orange{ER}}[/tex]
[tex]\orange{\underline{\huge{\bold{\textit{\green{\bf{REASON}}}}}}}[/tex]
The energy in the form of heat which is supplied to the body is used in the breaking of the bonds to change its State. when changing from low energy state to high energy state
The energy in the form of heat which is released out is released when bonds r formed to change the state . when changing from high energy state to low energy state.
so net change in temperature is zero bez the heat received and released is always used.
but whoever floosc is hmmmm you is fine
mmmmmmmmmmhhhhhhhhhhhhhhhhhhhh
metals and their ore
Answer:
Zinc
Zinc blende
(ZnS)
-----------------
Lead
Galena
(PbS)
-----------------
Mercury
Cinnabar
(HgS)
----------------
Copper
Copper glance
(Cu2S)
-------------------
Explanation:
Had to learn this for a test
Also, I plead the 5th
5. What type of pressure system____________and front____________are forming to have severe T-storms?
Answer:high pressure system and cold fronts
Explanation:
High pressure develops in areas where air cools and sinks. This usually causes fair weather with cool temperatures and few clouds.
Cold fronts occur when warm air is pushed up into the atmosphere by colder air at the ground. These fronts tend to move faster than the other types of fronts and are associated with the most violent types of weather such as severe and super cell thunderstorms, although any type of front can produce these same storms. After a cold front passes it is common to have clear skies and a dramatic change in wind direction on top of the cooler air associated with the front itself.
